Maria Shriver‘s brother Mark has been taking his big sister’s messy split from Arnold Schwarzenegger hard. Friends of Mark who have seen him at the Congressional Country Club in Bethesda, Md., say the normally gregarious head of Save the Children has been keeping to himself recently, even brushing off concerned friends. “His ego seems bruised by the whole thing,” a pal of his told us. “Losing his parents [Eunice and Sargent Shriver] was hard enough. I think he saw Arnold as the new patriarch of the family.” A rep for Mark didn’t get back to us.